The factors that affect the coating of
seamless pipes mainly include the following four points: the passive film of seamless steel pipes belongs to a suppressed metastable structure in thermodynamics, and its maintenance effect is related to the medium in the environment. But no matter what kind of environment it is used in, it should be cleaned regularly to remove harmful substances attached to the surface.
Chloride ions are very harmful to the coating of seamless steel pipes. We must strictly control the content of chloride ions in the passivation solution during the passivation process of the surface. Many chemical materials for passivation have limited requirements for chloride ions, and also have strict water quality requirements for chloride ions in the configuration of passivation solution water and cleaning water to ensure that the passivation waste products do not contain chloride ions.
The lower the nickel content in the seamless steel pipe, the lower the passivation performance, so the martensite content and the content of chromium and nickel have a great influence on the passivation performance of the rectangular tube surface. The more lubricated the surface of stainless steel, the lower the roughness, the harder it is for foreign matter to adhere, and the corrosion will be reduced to the lowest point, so the surface of the square tube should be finished as far as possible. In addition, the cleaning after passivation should be carried out carefully, so that the remaining acid solution can promote the anodic reaction, maintain the integrity of the film layer, and ensure that the corrosion resistance of the surface is enhanced.
In the production and transportation of seamless steel pipes, oil will inevitably adhere to the surface, which will affect the quality of rust removal and phosphating, and reduce the bonding force between the coating and the substrate. It mainly uses organic solvents to dissolve saponified and unsaponifiable oils to remove oil stains. Commonly used organic solvents are ethanol, gasoline for cleaning, toluene, carbon tetrachloride, trichloroethylene, etc. Among them, the more effective solvents are carbon tetrachloride and trichloroethylene, which do not burn and can be degreasing at higher temperatures.
Husteel Industry Group is a leading welded pipe and seamless pipe manufacturer & supplier serving diverse industries with multiple types, grades, diameters and lengths of pipe.
